Re: vc-resolve-conflicts is not flexible enough for alternate SCM systems

[Jonathan Kamens]

>  Date: Sat, 5 Jan 2002 22:29:02 -0500
>  From: Jonathan Kamens <jik@kamens.brookline.ma.us>
>  
>  3) Use these functions in vc-resolve-conflicts for producing the
>     buffers used by ediff.  If resolve-select-original returns true,
>     then call ediff-merge-buffers-with-ancestor instead of
>     editff-merge-buffers, and don't set ediff-default-variant.

I've changed my mind; I think it's safer to set ediff-default-variant
always.  New patch:

--- /usr/share/emacs/21.1/lisp/vc.el    Mon Sep 24 18:29:15 2001
+++ vc.el       Sun Jan  6 07:44:03 2002
@@ -1925,11 +1925,45 @@
   (if (zerop status) (message "Merge successful")
     (if (fboundp 'smerge-mode) (smerge-mode 1))
     (if (y-or-n-p "Conflicts detected.  Resolve them now? ")
-       (if (fboundp 'smerge-ediff)
+       (if (and (fboundp 'smerge-ediff)
+                (not (vc-find-backend-function (vc-backend file)
+                                               'resolve-select-yours)))
            (smerge-ediff)
          (vc-resolve-conflicts name-A name-B))
       (message "File contains conflict markers"))))
 
+(defun vc-default-resolve-select-yours (backend)
+  (goto-char (point-min))
+  (let ((found nil))
+    (while (re-search-forward (concat "^<<<<<<< "
+                                     (regexp-quote file-name) "\n") nil t)
+      (setq found t)
+      (replace-match "")
+      (if (not (re-search-forward "^=======\n" nil t))
+         (error "Malformed conflict marker"))
+      (replace-match "")
+      (let ((start (point)))
+       (if (not (re-search-forward "^>>>>>>> [0-9.]+\n" nil t))
+           (error "Malformed conflict marker"))
+       (delete-region start (point))))
+    found))
+
+(defun vc-default-resolve-select-theirs (backend)
+  (goto-char (point-min))
+  (while (re-search-forward (concat "^<<<<<<< "
+                                   (regexp-quote file-name) "\n") nil t)
+    (let ((start (match-beginning 0)))
+      (if (not (re-search-forward "^=======\n" nil t))
+         (error "Malformed conflict marker"))
+      (delete-region start (point))
+      (if (not (re-search-forward "^>>>>>>> [0-9.]+\n" nil t))
+         (error "Malformed conflict marker"))
+      (replace-match "")))
+  t)
+
+(defun vc-default-resolve-select-original (backend)
+  nil)
+
 (defvar vc-ediff-windows)
 (defvar vc-ediff-result)
 (eval-when-compile
@@ -1945,53 +1979,52 @@
   (vc-ensure-vc-buffer)
   (let* ((found nil)
          (file-name (file-name-nondirectory buffer-file-name))
+        (backend (vc-backend buffer-file-name))
         (your-buffer   (generate-new-buffer
                          (concat "*" file-name
                                 " " (or name-A "WORKFILE") "*")))
         (other-buffer  (generate-new-buffer
                          (concat "*" file-name
                                 " " (or name-B "CHECKED-IN") "*")))
+         (ancestor-buffer (generate-new-buffer
+                          (concat "*" file-name
+                                  " " (or name-B "ORIGINAL") "*")))
          (result-buffer (current-buffer)))
     (save-excursion
       (set-buffer your-buffer)
       (erase-buffer)
       (insert-buffer result-buffer)
-      (goto-char (point-min))
-      (while (re-search-forward (concat "^<<<<<<< "
-                                       (regexp-quote file-name) "\n") nil t)
-        (setq found t)
-       (replace-match "")
-       (if (not (re-search-forward "^=======\n" nil t))
-           (error "Malformed conflict marker"))
-       (replace-match "")
-       (let ((start (point)))
-         (if (not (re-search-forward "^>>>>>>> [0-9.]+\n" nil t))
-             (error "Malformed conflict marker"))
-         (delete-region start (point))))
-      (if (not found)
+      (if (not (vc-call-backend backend 'resolve-select-yours))
           (progn
             (kill-buffer your-buffer)
             (kill-buffer other-buffer)
+            (kill-buffer ancestor-buffer)
             (error "No conflict markers found")))
+      
       (set-buffer other-buffer)
       (erase-buffer)
       (insert-buffer result-buffer)
+      (vc-call-backend backend 'resolve-select-theirs)
+
+      (set-buffer ancestor-buffer)
+      (erase-buffer)
+      (insert-buffer result-buffer)
       (goto-char (point-min))
-      (while (re-search-forward (concat "^<<<<<<< "
-                                       (regexp-quote file-name) "\n") nil t)
-       (let ((start (match-beginning 0)))
-       (if (not (re-search-forward "^=======\n" nil t))
-           (error "Malformed conflict marker"))
-       (delete-region start (point))
-       (if (not (re-search-forward "^>>>>>>> [0-9.]+\n" nil t))
-           (error "Malformed conflict marker"))
-       (replace-match "")))
+      (if (not (vc-call-backend backend 'resolve-select-original))
+          (progn
+            (kill-buffer ancestor-buffer)
+           (setq ancestor-buffer nil)))
+
       (let ((config (current-window-configuration))
             (ediff-default-variant 'default-B))
 
         ;; Fire up ediff.
 
-        (set-buffer (ediff-merge-buffers your-buffer other-buffer))
+        (set-buffer
+        (if ancestor-buffer
+            (ediff-merge-buffers-with-ancestor your-buffer other-buffer
+                                               ancestor-buffer)
+          (ediff-merge-buffers your-buffer other-buffer)))
 
         ;; Ediff is now set up, and we are in the control buffer.
         ;; Do a few further adjustments and take precautions for exit.